The mechglue for gss_accept_sec_context suppresses error tokens which means that an initiator who is waiting for a response after receiving GSS_S_CONTINUE_NEEDED is never notified that there’s a problem.  It appears the code has been this way ever since the mechglue was introduced.  This fixes it for me:

Index: g_accept_sec_context.c

===================================================================

--- g_accept_sec_context.c         (revision 42878)

+++ g_accept_sec_context.c      (working copy)

@@ -385,9 +385,6 @@

                free(union_ctx_id);

     }

-    if (output_token->length)

-              (void) gss_release_buffer(&temp_minor_status, output_token);

-

     if (src_name)

                *src_name = GSS_C_NO_NAME;